docs: def _daily_suns(self, datetimes):
          """Get sun curve for multiple days of the year."""
          for dt in datetimes:
              # calculate sunrise sunset and noon
              nss = self.calculate_sunrise_sunset(dt.month, dt.day)
              dts = tuple(nss[k] for k in ('sunrise', 'noon', 'sunset'))
              if dts[0] is None:
                  # circle
                  yield (self.calculate_sun(dt.month, dt.day, h) for h in (0, 12,
                                                                           15)), \
                      False
              else:
                  # Arc
                  yield (self.calculate_sun_from_date_time(dt) for dt in dts), True